Transceiver and interface for ic package

ABSTRACT

An interconnect system includes a first circuit board, first and second connectors connected to the first circuit board, and a transceiver including an optical engine and arranged to receive and transmit electrical and optical signals through a cable, to convert optical signals received from the cable into electrical signals, and to convert electrical signals received from the first connector into optical signals to be transmitted through the cable. The transceiver is arranged to mate with the first and second connectors so that at least some converted electrical signals are transmitted to the first connector and so that at least some electrical signals received from the cable are transmitted to the second connector.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to transceivers and IC packages. Morespecifically, the present invention relates to transceivers that can bedirectly plugged into an IC package.

2. Description of the Related Art

FIG. 18 shows a conventional transceiver 500 and a conventionalintegrated circuit (IC) package 504. The transceiver 500 is connected toa socket 501 on a printed circuit board (PCB) 503. The IC package 504 isconnected to the PCB 503 through solder balls 504 a. The IC package 504is a ball grid array (BGA). The IC package 504 is connected to thesocket 501 by traces 502 located on or in the PCB 503. The transceiver500 includes an optical engine that provides optical-to-electrical andelectrical-to-optical conversion. That is, the electrical signalsreceived from the IC package 504 are converted to optical signals thatare transmitted through the optical fiber cable 500 a, and all opticalsignals received through the optical fiber cable 500 a are converted toelectrical signals and are transmitted to the IC package 504 through thetraces 502 on the PCB 503 and the solder balls 504 a.

Increased bandwidth demands make it difficult to transmit data to andfrom IC packages over copper connections, including the traces 502 shownin FIG. 18. Signals to and from the IC package have to travel over along distance. For example, an electrical signal transmitted by an ICdie (not shown in FIG. 18) of the IC package 504 has to be transmittedthrough an IC circuit board (not shown in FIG. 18), through solder balls504 a, along traces 504 on the PCB 503 to the socket 501, and finally tothe transceiver 500 where the electrical signals are converted tooptical signals and transmitted through the optical fiber cable 500 a.Optical signals transmitted from the optical fiber cable 500 a to thetransceiver 500 must follow the same lengthy path, but in reverse. Thelength of this path can reach up to 20 inches. High-end applications,such as switches, can use many transceivers, in which the optical andelectrical signals for each of the transceivers must travel similarlylengthy paths. This approach as shown in FIG. 18 with a lengthy path hasmany drawbacks, including:

-   -   1. Requiring more power to amplify or recover the data signals,        which increases the bit error rate and which creates some        limitations in the placements of components on the PCB, because        data signals have to travel over lossy copper traces on a PCB.    -   2. Increasing costs by increasing the number of components,        including connectors, transceiver cages, housing, etc. and        requiring a larger number of BGA connections between the IC        package and the PCB because all the data signals have to be        transmitted to and from the BGA of the IC package.

Known transceivers, including the conventional transceiver 500 shown inFIG. 18, cannot be adapted for connecting directly to an IC packagebecause known transceivers are not small enough or have adequatemechanical retention. Known transceivers require a large amount of spaceand consume hardware to mate or dock the optical engine. Knowntransceivers cannot be adapted to both on-board and ball grid array(BGA) stepped-plane environments. Size and geometry of knowntransceivers is limited by interference from low-speed signals and powersignals being carried in the same transceiver as the high-speed signals.

Known LGA connector systems require additional hardware to mate andoperate, including, for example, springs, fasteners, latch bars orlevers, latches for heat sinks. This hardware applies even compressionpressure over the top of connector systems. Springs are typically usedto allow for thermal expansion while applying and distributing force.Added hardware is typically used for alignment and ease of installationfor electrical, optical alignment, and mechanical reasons.

FIG. 19A shows a known IC package 514 that includes a socket 510 thatincludes a multi-fiber push-on (MPO) 511. The IC package 514 alsoincludes an IC die 515 and a circuit board 516 with solder balls 516 a.MPO 511 is an optical connector in which optical signals are inputtedand outputted. All the optical components, including those that convertoptical signals to electrical signals and convert electrical signals tooptical signals, must be located in the IC package 514 and cannot beeasily replaced if they fail. That is, the IC package 514 must include,in addition to MPO 511, a converter that converts optical signals toelectrical signals and that converts electrical signals to opticalsignals, which increases the size and cost of the IC package 514.Because the converter must be included in the IC package 514 when it ismanufactured, the converter must also be able to tolerate the reflowtemperatures used when the IC package 514 is connected to host circuitboard (not shown in FIGS. 19A and 19B). Further, the IC package fails ifeither the IC die 515 or the converter fails. FIG. 19B shows aconventional modification of the IC package 514 shown in FIG. 19A inwhich the conventional IC package 524 includes a socket 520 located onthe opposite side of the IC package 524 as the MPO 521. The socket 520and the MPO 521 are connected by fiber optic cables 527. The IC package524 includes an IC die 525 and a circuit board 526 with solder balls 526a. Because MPO 511 is an optical connector, MPO 511 is more expensivethan a copper connector, and is sensitive to dust and othercontamination. MPO 511 also requires expensive precision mechanicallatching to ensure proper alignment of the optical connector that mateswith the MPO 511. The mechanical latching causes the MPO 511 to besensitive to mechanical stress on the fibers connected to the MPO 511,which can create optical misalignment. The IC package 514 requires morestringent stiffness requirements compared to IC packages that can beused with copper connectors. In addition, the IC package 514 cannot betested electrically during production because only a very expensiveoptical tester can be used.

Known transceivers, which typically include an optical engine andtypically use pluggable connectors, are not designed to be directlyconnected to an IC package. Known transceivers are not small enough orhave adequate mechanical retention. Known transceivers require a largeamount of space and require hardware to mate or dock the optical engine.Known transceivers cannot be adapted to both on-board and ball gridarray (BGA) stepped-plane environments.

Typical transceivers have a single electrical connector that transmitsall of the high speed signals, the low speed signals, and the power andground signals, which limits miniaturization of the transceiver. KnownIC package connector systems require additional hardware to mate andoperate, including, for example, springs, fasteners, latch bars orlevers, latches for heat sinks. This hardware applies even compressionpressure over the top of the connector systems. Springs are typicallyused to allow for thermal expansion while applying and distributingforce. Added hardware is typically used for alignment and ease ofinstallation for electrical, optical alignment, and mechanical reasons.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of thepresent invention provide a transceiver that can be plugged directlyinto an IC package. Because the transceiver includes an optical enginethat can be unplugged from the IC package, none of the opticalcomponents need to be located within the IC package.

An interconnect system according to a preferred embodiment of thepresent invention includes a host circuit board, an IC package connectedto the host circuit board and including a first connector, an IC circuitboard, and an IC die, a transceiver including an optical engine arrangedto convert optical signals into electrical signals and arranged toconvert electrical signals into optical signals. The transceiver isarranged to mate with the first connector so that at least someelectrical signals transmitted to and from the IC die are transmittedonly on or through the IC circuit board.

The IC circuit board preferably includes a plurality of solder ballsarranged in a ball grid array. The interconnect system preferablyfurther includes a second connector connected directly to the hostcircuit board and arranged to connect the transceiver directly to thehost circuit board so that at least some electrical signals received bythe transceiver are transmitted directly to the host circuit board. Thesecond connector preferably is a zero-insertion-force connector. Thesecond connector can include a latch that is arranged to connect thetransceiver to the second connector. The second connector can include aclip that is arranged to connect the transceiver to the secondconnector. The second connector and the transceiver can be connectedwith a screw, for example.

The first connector is preferably an edge-card connector. Thetransceiver preferably further includes a heatsink. The transceiverpreferably further includes a transceiver circuit board, and theheatsink preferably includes a pair of legs that are arranged to connectthe transceiver circuit board to the heat sink, preferably includes apair of protrusions and a strap that are arranged to connect thetransceiver circuit board to the heat sink, or preferably includes apair of opposing clips that are arranged to connect the transceivercircuit board to the heat sink. The transceiver is preferably connectedto the host circuit board with a screw, for example.

The IC package preferably further includes a lid. The lid preferablyprovides a heat path for the optical engine when the transceiver ismated with the first connector. The transceiver preferably includes acable through which the transceiver receives and transmits opticalsignals. The optical signals are preferably converted to electricalsignals and transmitted to the IC package through the first connector.The electrical signals are preferably further transmitted to the IC diethrough the first connector and the IC circuit board. The electricalsignals are preferably transmitted directly to the host circuit boardthrough a second connector connected to the host circuit board. Thetransceiver preferably includes a cable through which the transceiverreceives and transmits electrical signals.

The IC package preferably includes at least one additional firstconnector.

An interconnect system according to a preferred embodiment includes afirst circuit board, first and second connectors connected to the firstcircuit board, and a transceiver including an optical engine andarranged to receive and transmit optical signals through a cable, toconvert optical signals received from the cable into electrical signals,and to convert electrical signals received from the first connector intooptical signals to be transmitted through the cable. The transceiver isarranged to mate with the first and second connectors so that at leastsome converted electrical signals are transmitted to the first connectorand so that at least some electrical signals received from the cable aretransmitted to the second connector.

The first connector can be connected to the first circuit board througha second circuit board. The transceiver is preferably arranged toreceive and transmit electrical signals through the cable. The cable ispreferably permanently attached to the transceiver.

A system according to a preferred embodiment of the present inventionincludes a host circuit board, a package including first and secondconnectors, and a third connector connected to the host circuit boardbut not connected to the package. The package is surface mounted to thehost circuit board through the first connector. The second connector isconnected to the package but is not connected to the host circuit board.The system can transmit electrical signals or only optical signals orboth electrical and optical signals.

The system preferably further includes a transceiver including a fourthconnector arranged to mate with the second connector, an interfacearranged to mate with the third connector, a cable including at leastone optical fiber, and an optical engine arranged to convert at leastsome electrical signals received from the second connector into opticalsignals and transmit the converted optical signals to the at least oneoptical fiber and arranged to convert optical signals received from theat least one optical fiber into electrical signals and transmit theconverted electrical signals to the second connector. The cable ispreferably permanently attached to the optical engine.

The transceiver preferably includes at least one copper cable that ispermanently attached to the fourth connector.

The third connector preferably provides mechanical retention for thetransceiver. The third connector provides latching for the transceiver.The third connector preferably provides electrical connections betweenthe transceiver and the host circuit board without going through thepackage. The third connector provides electrical connections between thetransceiver and the host circuit board without going through the packageand provides mechanical retention.

The above and other features, elements, characteristics and advantagesof the present invention will become more apparent from the followingdetailed description of preferred embodiments of the present inventionwith reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a conceptual drawing of an IC package and a transceiveraccording to a preferred embodiment of the present invention beforebeing mated together.

FIG. 1B is a conceptual drawing of an IC package and a transceiveraccording to a preferred embodiment of the present invention matedtogether.

FIG. 1C is a conceptual drawing of an IC package and a transceiveraccording to a preferred embodiment of the present invention matedtogether.

FIG. 1D is close-up sectional view of an IC package and a transceiveraccording to a preferred embodiment of the present invention.

FIG. 1E is close-up view of an IC package and a transceiver according toa preferred embodiment of the present invention.

FIGS. 2A and 2B show a circuit board for use in an IC package accordingto the first and second preferred embodiments of the present invention.

FIGS. 2C and 2D show a lid for use with an IC package according to thefirst and second preferred embodiments of the present invention.

FIGS. 3A-3D show a transceiver and an IC package according to the firstpreferred embodiment of the present invention.

FIGS. 4A-4C show a transceiver and an IC package according to the secondpreferred embodiment of the present invention.

FIGS. 5A and 5B shows a transceiver for use with the third througheighth preferred embodiments of the present invention.

FIG. 5C is a circuit board for use with the third, fifth, and seventhpreferred embodiments of the present invention.

FIG. 5D is a circuit board for use with the fourth, sixth, and eighthpreferred embodiments of the present invention.

FIGS. 6A and 6B show a heatsink for use with the third and fourthpreferred embodiments of the present invention.

FIGS. 6C and 6D show a transceiver with a heatsink for use with thethird and fourth preferred embodiments of the present invention.

FIGS. 7A and 7B show a circuit board and a transceiver according to thethird preferred embodiment of the present invention.

FIGS. 8A and 8B show a circuit board and a transceiver according to thefourth preferred embodiment of the present invention.

FIGS. 9A and 9B show a heatsink for use with the fifth and sixthpreferred embodiments of the present invention.

FIGS. 9C and 9D show a transceiver with a heatsink for use with thefifth and sixth preferred embodiments of the present invention.

FIGS. 9E and 9F show modified transceivers with a heatsink for use withthe fifth and sixth preferred embodiments of the present invention.

FIGS. 10A-10D show circuit boards and transceivers according to thefifth preferred embodiment of the present invention.

FIGS. 11A-11D show circuit boards and transceivers according to thesixth preferred embodiment of the present invention.

FIGS. 12A and 12B show a heatsink for use with the seventh and eighthpreferred embodiments of the present invention.

FIGS. 12C and 12D show a transceiver with a heatsink for use with theseventh and eighth preferred embodiments of the present invention.

FIGS. 13A and 13B show a circuit board and a transceiver according tothe seventh preferred embodiment of the present invention.

FIGS. 14A and 14B show a circuit board and a transceiver according tothe eighth preferred embodiment of the present invention.

FIGS. 15A and 15B show a heatsink for use with the ninth and tenthpreferred embodiments of the present invention.

FIGS. 15C and 15D show a U-clip for use with the ninth and tenthpreferred embodiments of the present invention.

FIGS. 15E and 15F show a transceiver with a heatsink for use with theninth and tenth preferred embodiments of the present invention.

FIGS. 16A and 16B show a circuit board and a transceiver according tothe ninth preferred embodiment of the present invention.

FIGS. 17A and 17B show a circuit board and a transceiver according tothe tenth preferred embodiment of the present invention.

FIG. 18 shows a conventional transceiver and a conventional IC package.

FIG. 19A shows another conventional IC package.

FIG. 19B shows a conventional modification of the IC package shown FIG.19A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1A-1E are conceptual drawings of the IC package 10 and thetransceiver 15 according to a preferred embodiment of the presentinvention. FIG. 1A shows an IC package 10 and a transceiver 15 beforebeing mated together, while FIG. 1B shows the IC package 10 and thetransceiver 15 mated together. The IC package 10 includes an IC die 12and an enclosure (e.g., lid 11 and circuit board 13) for protecting theIC die 12 and electrical contacts (e.g., solder balls 13 a) fortransmitting electrical signals in a larger overall system. Thetransceiver 15 includes an optical engine 15 a and is connected to cable16. The cable 16 preferably includes a plurality of fiber optic cables.It is also possible for the cable 16 to include, in addition to fiberoptic cables, one or more copper cables. The optical engine 15 aconverts optical signals into electrical signals and electrical signalsinto electrical signals. The optical engine 15 a is preferably apluggable optical engine that includes 4, 8, or 12 channels and that canbe surface mountable. However, the optical engine 15 a can have anynumber of channels. Although current channels have a maximum speed ofabout 10 Gbps, higher maximum speeds will be achievable in the future,and thus the speed of the channels of the optical engine 15 a is notlimited. The optical engine 15 a can be surface mountable. Examples ofthe optical engines 15 a are disclosed in U.S. Pat. Nos. 7,329,054;7,648,287; 7,766,559; and 7,824,112; U.S. Patent Application PublicationNos. 2008/0222351, 2011/0123150, and 2011/0123151; and U.S. ApplicationNo. 61/562,371, the entirety of the contents of which are herebyincorporated by reference.

FIG. 1C shows a modification of the arrangement of the IC package 10 andtransceiver 15 shown in FIGS. 1A and 1B in which a connector 18 aconnects the transceiver 15 directly to the host circuit board 18,without going through the IC package 10. In this arrangement, signalscan be transmitted directly to the host circuit board 18 without goingthrough the IC package 10.

If the cable 16 includes one or more copper cables, then power can betransmitted through the transceiver 15. The power can be transmittedto/from the IC package 10 or could be transmitted directly to/from thehost circuit board 18 through the connector 18 a. If power istransmitted directly the host circuit board 18, then it is possible thatthe power can be further transmitted to the IC package 10.

It is also possible to transmit signals through the copper cablesdirectly to the host circuit board 18 without going through the ICpackage 10. It is also possible for the optical signals to betransmitted through the cable 16. It is also possible for the opticalsignals to be converted into electrical signals, and for the convertedelectrical signals to be transmitted directly to the IC package 10through socket 14 and/or directly to the host circuit board 18 throughthe connector 18 a.

The IC package 10 shown in FIGS. 1A-1C preferably is a BGA package;however, the IC package 10 could be any suitable package type, includingflip-chip BGA package, dual in-line package, pin grid array package,leadless chip carrier package, surface mount package, small-outline ICpackage, plastic leaded chip carrier package, plastic quad flat packpackage, or thin small-outline package. The IC package 10 preferablyincludes a lid 11, an IC die 12, a circuit board 13, and a socket 14.The lid 11 can act as a heat sink for both the IC package 10 and thetransceiver 15 and preferably covers the IC die 12, at least a portionof the circuit board 13, and at least a portion of the socket 14. It ispossible to use a separate heatsink (not shown in FIGS. 1A-1C) insteadof or in addition to the lid 11. The lid 11 can be arranged to ensurethat the transceiver 15 is pressed in the socket 14.

Although only one IC die 12 is shown in FIGS. 1A-1C, it is possible touse two or more IC dies 12.

The circuit board 13 preferably includes solder balls 13 a arranged inBGA for connecting the IC package 10 to the host circuit board 18. Thesocket 14 preferably extends through an opening through the lid 11 sothat the transceiver 15 can be mated with the socket 14, as shown inFIG. 1B. Although only one socket 14 and transceiver 15 are shown inFIGS. 1A-1C, it is possible to use two or more sockets 14 andtransceivers 15. The sockets 14 can be located on the same side ordifferent sides of the IC package 10.

The lid 11 of the IC package 10 preferably provides a path for heatdissipation, as shown in FIG. 1D. FIG. 1D is a close-up view showing apossible arrangement of the socket 14 and transceiver 15. In FIG. 1D,the lid 11 and the socket 14 provide a cavity such that, when thetransceiver 15 is inserted into the socket 14, (1) the electricalconnection between the transceiver 15 and the socket 14 is assured bythe upward compression force of the electrical contacts and (2) the heatdissipates along the path provided between the transceiver 15 and thelid 11. There is a heat path directly from the transceiver 15 to the lid11. As shown in FIG. 1D, optical signals can be transmitted to and fromthe transceiver 15 through cable 16, and electrical signals can betransmitted between the IC die 12 and transceiver 15 and between the ICdie 12 and the host circuit board 18, which, although not shown in FIG.1D, would be connected to the circuit board 13 through solder balls 13a.

FIG. 1E is a sectional view of a possible arrangement of the transceiver15 and the IC package 10. FIG. 1E shows the IC package 10 preferablyincluding four sockets 14, for example, three of which are shown in thefigure. One of the sockets 14 can be arranged along the upper rightsurface of the lid. The IC package 10 includes an IC die 12 located on acircuit board 13 that includes solder balls 13 a. The lid 11 includes afinger 11 a that provides a heat path from the IC die 12 to the lid 11.As with FIG. 1D, the socket 14 in FIG. 1E is arranged to provide acavity such that, when the transceiver 15 is inserted into the cavity, aheat path is provided from the transceiver 15 to the lid 11. That is,the lid 11 provides heat paths for both the IC die 12 and thetransceiver 15.

Using the IC package 10 and the transceiver 15 it is possible totransmit some or all of the data signals from the cable 16 to the IC die12 without transmitting the data signals through the solder balls 13 aof the IC package 10 or through the host circuit board 18. Because ofthe proximity of the transceiver 15 to the IC die 12, the IC package 10needs much lower output amplification of the data signals. Similarly inthe transceiver 15, higher data rates are possible because of thelimited amount of dispersion in the short electrical path between thetransceiver 15 and the IC die 12. Lower product and packaging cost canbe achieved because: 1) fewer BGA connections are required because someor all the high speed data signals are not routed through solder balls13 a of the IC package 10 or through the host circuit board 18, 2) lesscomplexity of the host circuit board 18 and less cost because fewer datasignals need to be routed through the solder balls 13 a of the ICpackage 10 and the host circuit board 18. Increased data signal densitycan be achieved because of the miniaturization of the transceiver 15.The IC package 10 can be reflowed without the transceiver 15, so thereis no need for the transceiver 15 to withstand reflow temperatures. Thatis, the transceiver 15 can be added after the IC package 10 is connectedto the host circuit board 18.

The IC package 10 and the transceiver 15 can be tested separately,minimizing yield loss. The transceiver 15 can be replaced if it fails.Similarly, the transceiver 15 can be re-used after an IC package 10 isreplaced. The optical connections can be re-routed without redesigningthe host circuit board 18. The IC package 10 can be electrically testedusing conventional methods. The transceiver 15 and cable 16 are addedlast, making handling easier and allowing greater manufacturing freedombecause the IC package 10 does not include any optical fiber or cableextending from it.

The optical signals within the transceiver 15 and optical connectionsare preferably never exposed. Optical connectors have surfaces that canget dirty, which can make the optical connection not perform or havedegraded performance. By not exposing the optical connections, properperformance can be assured. There are no fragile optical connectionsbetween the transceiver 15 and the IC package 10. Because opticalconnectors are expensive, it is possible achieve cost savings byreducing the number of optical connectors. The transceiver 15 and thesocket 14 can be designed as standard components with standardinterfaces and circuit board footprints. Packaging of new IC packages 10only requires the redesign of the routing of circuit board 13, of theBGA layout, and of the lid 11 of the new IC package 10. No change intooling or fixturing is required for the transceiver 15 or the socket14.

The end opposite of the optical engine 15 a of the transceiver 15 can becustomized to use any suitable connector, including, for example, MPO,LC or FC fan-out, Prizm connector, other suitable transceiver(s), etc.

A multi-channel (e.g., 12 or other) half-duplex transceiver would alsoyield a highly modular system, allowing customization of the number ofinput and outputs (I/Os) for different ICs. Similarly, a singlesecondary electrical connector design could be used for a 12-channelhalf-duplex transceiver or a 4- to 6-channel full-duplex transceiver.

The transceiver 15 according to any of various preferred embodiments ofthe present invention can be inserted into a IC package 10 according toany of various preferred embodiments of the present invention and caninclude any of the following:

-   -   1. The socket 14 of the IC package 10 can be an electrical        connector for connecting the transceiver 15 to the IC package        10.    -   2. The transceiver 15 shares the IC package's 10 heatsink(s).    -   3. The transceiver 15 has its own heatsink(s).    -   4. The transceiver 15 has electrical connections on one side and        a thermal dissipation surface on another side.    -   5. The transceiver 15 is permanently attached to a single or a        plurality of optical fibers.    -   6. The transceiver 15 can include an electrical connector as        well as an optical connector for receiving an optical patchcord.

The IC package 10 can include data signal connection(s) that connect theIC die to the socket(s) 14, without going through the IC package 10 orthe host circuit board 18. The IC packages 10 can include the datasignal connections(s) that connect the host circuit board 18 directly tothe socket(s) 14, without going through the IC die 22. This provides asimple socket design, which is useful for testing and/or manufacturing.

The IC package 10 might not have an IC die 12 inside and could justtransmit data from the host circuit board 18 to the transceiver 15 andprovide thermal management.

The transceivers 15 preferably are miniature/low-costedge-connector-to-optical-engine board connectors, can be directlyconnected to an IC package, and are small, fast, less complicated, fewerparts or components, and have sufficient mechanical retention. Thetransceiver 15 preferably does not require a large amount of space formating the optical engine 15 a and preferably can be adapted to bothon-board and ball grid array (BGA) stepped-plane environments. Thetransceiver 15 is preferably not limited by interference from low-speedsignals and power signals being carried in the same transceiver 15 asthe high-speed signals.

The transceiver 15 and IC package 10 preferably do not requireadditional hardware to mate and operate. The size of the transceiver 15is preferably compatible with mating the transceiver 15 at the edge ofan IC package 10. The transceivers 15 and IC packages 10 can be matedwith little insertion force.

The connector system discussed above that only uses the socket 14 asshown in FIGS. 1A and 1B is a one-piece connector system. However, atwo-piece connector system can also be used, as shown in FIG. 1C. Thetwo-piece connector system includes, for example, the socket 14 and theconnector 18 a as shown, for example, in FIG. 1C. In the two-piececonnector system, both the transceiver 15 and a high data ratetransmission copper cables can be accommodated. The socket 14 can be anedge-card connector, and the connector 18 a can be azero-insertion-force compression connector so that the transceiver 15 ispushed into the socket 14, then pressed down with zero insertion forceinto the connector 18 a. The transceiver 15 and the IC package 10 can beused with various latching features discussed below, but with nocompression hardware required. Because there is no compression hardwarerequired, installation is simplified, component count is reduced, and amore commercially viable solution is provided. The transceivers 15 arepreferably capable of holding the weight of a heatsink (shown, forexample, as heatsink 25 c in FIG. 4B) required for the optical engine 15a.

The transceivers 15 can separate high-speed signals from low-speedsignals and/or power. Preferably, the high-speed signals are locatedwithin portion of the transceiver 15 that mates with the socket 14, andthe low-speed signals and/or power signals are located within theportion of the transceiver 15 that mates with the connector 18 a. Thisseparation of signals can simplify board implementation, can enhancesignal integrity, and can result in less hardware being used.

Space on the IC package 10 is limited to the length, width, and heightof the socket 14. Because less space is required, a less expensive andmore widely usable and marketable solution is provided. The length ofthe socket 14 is preferably less than about 11.25 mm, for example, whichallows multiple, for example, at least four, connections to an ICpackage 10. The socket 14 can be a 0.5 mm pitch edge-card connector, andthe connector 18 a can be a 0.8 mm pitch compression connector, forexample.

The IC package 10 can be, for example, a typical field-programmable gatearray (FPGA) package with sides having a dimension of about 45 mm, whichallows for eight transceivers (four on each of two sides). The height ofthe socket 14 is comparable to the typical height of an IC package 10,including an FPGA package, which is usually within the range of about0.75 mm to about 2.2 mm, for example. The socket 14 preferably has adepth that is as small as possible because the smaller the depth of thesocket 14, the smaller the IC package 10 can be to accommodate thesocket 14. Currently, the socket 14 with a depth of about 0.95 mm toabout 2.45 mm, for example, is preferred; however, it is possible thatin the future even smaller depths can be used.

The two-piece connector systems can be used in multiple environments,including a stepped-plane environment (e.g., BGA, LGA, and PGAapplications) and a flat, co-planar environment (e.g., on-boardapplications in which the two connectors are on the same circuit board).In the stepped-plane environment, the two connectors are located on twodifferent circuit boards. Preferably, the first circuit board is a hostcircuit board, and the second circuit board is included in an IC packagewith a BGA such that the top surface of the second circuit board islocated above the top surface of the host circuit board, i.e., thesecond circuit board is stepped up with respect to the host circuitboard. In the flat, co-planar environment, the two connectors arelocated on the same circuit board. This multiple environment use allowsthe two-piece connector system to be usable in multiple markets. Thereare no known solutions that allow direct mating to an IC package.

The two-piece connector system can separate high-speed signals fromlow-speed signals and/or power. The high-speed signals can be separatedusing, for example, a 0.50 mm pitch edge-card connector, and thelow-speed signals and/or power can be separated using a 0.80 mm pitchcompression connector.

The one-piece and two-piece connector systems can be used in any signaltransmission system, including any multiple high-speed cables inside thebox product using, for example, insulation-displacement connector (IDC),shielded IDC, twisted pair, shielded twisted pair, power, optical fiber(glass and plastic) flex, conductive elastomer, lead wire, shielded andunshielded cables, coaxial cables, twinaxial cables, and laminatedmicro-stripline and microstrip.

The first and second preferred embodiments of the present invention willnow be described. The first and second preferred embodiments of thepresent invention are similar with the main difference being differentconnectors being used for the socket 14. In the first preferredembodiment, a land grid array (LGA) connector 24 a is preferably used,and in the second preferred embodiment, an edge-card connector 24 b ispreferably used.

FIGS. 2A and 2B show a circuit board 23 for use with an IC packageaccording to the first or the second preferred embodiment of the presentinvention, and FIGS. 2C and 2D show a lid 21 for use with an IC packageaccording to the first or the second preferred embodiments of thepresent invention. As shown in FIG. 2A, the circuit board 23 includesareas 23 b where LGA connector 24 a (shown in FIG. 3A) or whereedge-card connectors 24 b (shown in FIG. 4A) corresponding to the socket14 of FIGS. 1A-1E can be located. As with the sockets 14 discussedabove, any number of LGA connectors 24 a or edge-card connectors 24 bcan be used. The circuit board 23 also includes areas 23 c where an ICdie 22 (shown in FIGS. 3A and 4A) can be located. As shown in FIG. 2B,the back of the circuit board 23 includes an array of solder balls 23 a.

FIGS. 2C and 2D show a lid 21 for covering the circuit board 23 shown inFIGS. 2A and 2B that can be used in either the first or second preferredembodiments. As seen in FIG. 2D, the bottom of the lid 21 preferablyincludes a finger 21 a. The finger 21 a is arranged to provide a heatpath for the IC die 22 when the lid 21 covers the circuit board 23 andwhen the IC die 22 is placed in the area 23 c of the circuit board 23.If two or more IC dies 22 are used, then the lid 21 can have two or morecorresponding fingers 21 a.

FIGS. 3A-3D show the transceiver 25 and the IC package 20 according to afirst preferred embodiment of the present invention. FIG. 3A shows acircuit board 23 with four LGA connectors 24 a, for example. AlthoughFIG. 3A shows two pairs of LGA connectors 24 a located on opposite sidesof the circuit board 23, any number of LGA connectors 24 a could be usedand any arrangement of LGA connectors 24 a could be used. For example,it is possible to arrange the four LGA connectors 24 a on differentsides of the circuit board 23 or to arrange the four LGA connectors 24 aon the same side of the circuit board 23. The possible arrangements ofthe LGA connectors 24 a are affected by the size of the circuit board 23of the IC package 20. For example, it is possible that the circuitboard's 23 size is small enough that only one LGA connector 24 a willfit on a side of the circuit board 23. The LGA connectors 24 a arearranged such that when the transceiver 25 is inserted into them the topof the optical engine 25 a is pressed against the lid 21 to form a heatpath in a similar manner as the heat path shown in FIG. 1D.

The circuit board 23 shown in FIGS. 3A and 3C does not include an IC die22 in the area 23 c. However, as explained above, a single IC die 22could be used, or more than one IC die 22 could be used.

FIG. 3B shows a transceiver 25 that preferably includes a tab 25 b. Thetab 25 b allows the transceiver 25 to be inserted and removed from theIC package 20. The transceiver 25 also includes an optical engine 25 athat converts optical signals to electrical signals and convertselectrical signals into optical signals. The optical engine 25 a isconnected to cable 26 that transmits optical signals. Cable 26preferably includes one or more fiber optic cables.

FIG. 3C shows the transceiver 25 inserted into the IC package 20, wherethe IC package 20 does not include the lid 21, and FIG. 3D shows thetransceiver 25 inserted into the IC package 20, where the IC package 20includes the lid 21. The optical engine 25 a receives optical signalsfrom the cable 26 and transmits the converted electrical signals to theIC die 22 through the LGA connector 24 a and the circuit board 23, andthe optical engine 25 a receives electrical signals from the IC die 22through the LGA connector 24 a and the circuit board 23 and transmitsthe converted optical signals to the cable 26.

FIGS. 4A-4C show the transceiver 25 and the IC package 20 according to asecond preferred embodiment of the present invention. In the secondpreferred embodiment, an edge-card connector 24 b is used instead of LGAconnector 24 a, and a heatsink 25 c is used instead of tab 25 b. FIG. 3Ashows a circuit board 23 with four edge-card connectors 24 b, forexample. As with the LGA connectors 24 a, any number of edge-cardconnectors 24 b could be used and any arrangement of edge-cardconnectors 24 b could be used. The circuit board 25 d can be insertedinto the edge-card connectors 24 b. In this preferred embodiment, theoptical engine 25 a is provided outside of the IC package 20. Becausethe optical engine 25 a is outside of the IC package 20, the lid 21cannot provide a heat path for the optical engine 25 a. Accordingly, thetransceiver 25 preferably includes the heatsink 25 c to provide a heatpath for heat dissipation for the optical engine 25 a.

The circuit board 23 shown in FIGS. 4A and 4C includes an IC die 22 inthe area 23 c. However, as explained above, a single IC die 22 could beused, or more than one IC die 22 could be used.

FIG. 4B shows a transceiver 25 that preferably includes a heatsink 25 cand circuit board 25 d. The transceiver 25 includes an optical engine 25a that converts optical signals to electrical signals and convertselectrical signals into optical signals. The heatsink 25 c can be usedto insert and remove the transceiver 25 from the IC package 20 andprovides a heat path for heat dissipation from the optical engine 25 a.The heatsink 25 c can also protect the optical engine 25 a and serve asa housing. The optical engine 25 a is connected to cable 26 thattransmits optical signals. Cable 26 preferably includes one or morefiber optic cables.

FIG. 4C shows the transceiver 25 inserted into the IC package 20, wherethe IC package 20 only includes the outer wall of the lid 21. Theoptical engine 25 a receives optical signals from the cable 26 andtransmits the converted electrical signals to the IC die 22 through theedge-card connector 24 b and the circuit board 23, and the opticalengine 25 a receives electrical signals from the IC die 22 through theedge-card connector 24 b and the circuit board 23 and transmits theconverted optical signals to the cable 26.

The third through tenth preferred embodiments of the present inventionwill now be described. The third through tenth preferred embodiments ofthe present invention are similar to the above-described preferredembodiments of the present invention, with the main differences beingthe environment in which the transceivers are used and the method inwhich the transceivers are attached to the circuit board(s). Thetransceivers can be used in either a flat, co-planar environment with asingle circuit board as shown, for example, in FIG. 5C or astepped-plane environment with two circuit boards as shown, for example,in FIG. 5D. The transceivers can be attached to the circuit board(s)using latches 135, 145 as shown, for example, in FIGS. 7B and 8B, clips155, 165 as shown, for example, in FIGS. 10C and 11C, screws 175 asshown, for example, in FIGS. 13B and 14B, or U-clip 191 d as shown, forexample, in FIGS. 16B and 17B. Some of the figures show connectors, e.g.front connector 152 in FIG. 10B, that, for simplicity, only include someof the contacts. It should be understood that the connectors can have afull set of contacts.

FIG. 5A shows an optical engine 115 a connected to cable 116 that can beused with each of the third through tenth preferred embodiments. Thetransceiver 115 includes an optical engine 115 a connected to a cable116. The optical engine 115 a is preferably a pluggable optical enginethat includes 4, 8, or 12 channels and that can be surface mountable.However, the optical engine 115 a can have any number of channels.Although current channels have a maximum speed of about 10 Gbps, highermaximum speeds will be achievable in the future, and thus the speed ofthe channels of the optical engine 115 a is not limited. Examples of theoptical engine 115 a are disclosed in U.S. Pat. Nos. 7,329,054;7,648,287; 7,766,559; and 7,824,112; U.S. Patent Application PublicationNos. 2008/0222351, 2011/0123150, and 2011/0123151; and U.S. ApplicationNos. 61/562,371, the entirety of which are hereby incorporated byreference. Cable 116 can include only one or more fiber optic cables,only one or more copper cables, or a combination of one or more fiberoptic cables and one or more copper cables. FIG. 5B shows the opticalengine 115 a with a circuit board 115 b. The transceiver 115 includes aheatsink (not shown in FIG. 5B) that is used to dissipate the thermalload. The circuit board 115 b preferably includes lands 115 c, 115 d,115 e (only land 115 c on the top of the circuit board 115 b is shown inFIG. 5B) and an IC chip 115 f. The IC chip 115 f can route and/or modifythe electrical signals transmitted to and from the transceiver 115,including conditioning the electrical signals for protocol specific datatransfers. Lands 115 d, 115 e are located on the bottom of the circuitboard 115 b. Lands 115 d are located on the bottom of the circuit board115 b opposite of the lands 115 c. Lands 115 e are located on the bottomof the circuit board 115 b, near the end of the circuit board 115 bopposite to the end with the lands 115 d, 115 e. The circuit board 115 bcan also include notches 115 j that can be used with the latches 135 ofthe third and fourth preferred embodiments to connect the circuit board115 b to the back connectors 134, 144 as discussed below.

FIG. 5C shows a circuit board 118 for use in a flat, co-planarenvironment, and FIG. 5D shows circuit boards 119 a, 119 b for use in astepped-plane environment. The circuit board 118 includes lands 118 a,118 b and holes 118 c, 118 d. The circuit board 119 a includes lands 119c and holes 119 e, and the circuit board 119 b includes lands 119 d andholes 119 f. The holes 119 e, 119 f provide alignment for the twoconnectors when the two connectors are attached to the circuit boards119 a, 119 b. However, it is to possible use circuit boards 118 a, 119a, 119 b with any arrangement and number of lands 118 a, 118 b, 119 c,119 d and holes 118 c, 118 d, 119 e, 119 f. It is also possible tocircuit boards 118 a, 119 a, 119 b without holes 118 c, 118 d, 119 e,119 f.

The lands 118 a, 118 b, 119 c, 119 d provide electrical connections forthe two connectors of the two-piece connector systems, can be arrangedin any suitable arrangement, and can include any number of individuallands. As shown in FIGS. 5C and 5D, the lands 118 a, 118 b, 119 c, 119 dcan be arranged in two rows, but it is also possible that lands 118 a,118 b, 119 c, 119 d are arranged in a single row or more than two rows.Individual lands in different rows can have the same number ofindividual lands or a different number of individual lands.

The holes 118 c, 118 d, 119 e, 119 f, if used, can provide alignment forthe two connectors of the two-piece connector systems when the twoconnectors are attached to the circuit boards 118, 119 a, 119 b. Theholes 118 c, 118 d, 119 e, 119 f can be arranged in any suitablearrangement, can include any number of holes, and can have any suitablesize and shape. The holes 118 c, 118 d, 119 e, 119 f can be polarized toensure the proper alignment of the connector when the connector isattached to the circuit boards 118, 119 a, 119 b.

FIGS. 6A and 6B show a heatsink 131 for use with the transceiver 130shown in FIGS. 6C and 6D. The transceiver 130 is used in the third andfourth preferred embodiments of the present invention. The transceiver130 can be used in the flat, co-planar environment of the thirdpreferred embodiment shown in FIGS. 7A and 7B and can be used in thestepped-plane environment of the fourth preferred embodiment shown inFIGS. 8A and 8B.

As shown in FIGS. 6A and 6B, the heatsink 131 includes fins 131 a todissipate heat from the optical engine 115 a, legs 131 b to secure thecircuit board 115 b, cavity 131 c in which the optical engine 115 a islocated, and notches 131 d that engage with the latches 135 shown FIGS.7A-8B. Any suitable arrangement and number of fins 131 a can be used aslong as an adequate amount of heat can be dissipated from the opticalengine 115 a. Any arrangement and number of legs 131 b can be used tosecure the circuit board 115 b to the heatsink 131. For example, it ispossible to form the legs 131 b with a bend to secure the circuit board115 b as shown, for example, in FIGS. 6A-6D, and it is possible to formstraight legs 13 b and then swage the legs around the circuit board 115b. Any suitable shape and arrangement of the notches 131 d can be usedto secure the transceiver 130 to the circuit boards 118, 119 a.

FIGS. 7A and 7B show a two-piece connector system according to the thirdpreferred embodiment of the present invention. FIG. 7A shows the circuitboard 118 with the front connector 132 and the back connector 134.

The front connector 132 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, the frontconnector 132 includes two rows of contacts 132 a, with one row ofcontacts 132 a that can engage the lands 115 c on top of the circuitboard 115 b and with the other row contacts 132 a that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 134 is preferably a zero-insertion-force connectorthat includes latches 135 that can be used to secure the back portion ofthe transceiver 130 (not shown in FIG. 7A but shown in FIG. 7B) to thecircuit board 118. The back connector 134 includes a row of contacts 134a that can engage the lands 115 e on the bottom of the circuit board 115b. Although a single row of contacts 134 a is shown in FIG. 7A, it isalso possible to use more than one row of contacts 134 a.

To mate transceiver 130 with the circuit board 118, the circuit board115 b is pressed down into the back connector 134 aligning latches 135with notches 115 j in the circuit board 115 b, and then the circuitboard 115 b is pushed forward so that the front end of the circuit board115 b is inserted into the front connector 132 and the latches 135engage with the notches 131 d. To unmate the transceiver 130 from thecircuit board 118, the front end of the circuit board 115 b is pulledout of the front connector 132 such that the latches 135 disengage withthe notches 131 d and align with the notches 115 j, and then thetransceiver 130 is pulled out of the back connector 134. Preferably, thehigh-speed signals are transmitted through the front connector 132, andlow-speed signals and/or power are transmitted through the backconnector 134.

FIGS. 8A and 8B show a two-piece connector system according to thefourth preferred embodiment of the present invention. FIG. 8A shows thecircuit board 119 b with the front connector 142 and the circuit board119 a with the back connector 144. The circuit board 119 b can be partof an IC package; however, for simplicity, only the circuit board 119 ais shown.

The front connector 142 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, the frontconnector 142 includes two rows of contacts 142 a, with one row ofcontacts 142 a that can engage the lands 115 c on top of the circuitboard 115 b and with the other row contacts 142 a that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 144 is preferably a zero-insertion-force connectorthat includes latches 145 that can be used to secure the back portion ofthe transceiver 130 (not shown in FIG. 8A but shown in FIG. 8B) to thecircuit board 119 a. The back connector 144 can be similar to the backconnector 134 with the difference being that the height of the backconnector 144 is larger than the height of the back connector 134. Theback connector 144 includes a row of contacts 144 a that can engage thelands 115 e on the bottom of the circuit board 115 b. Although a singlerow of contacts 144 a is shown in FIG. 8A, it is also possible to usemore than one row of contacts 144 a.

To mate transceiver 130 with the circuit boards 119 a, 119 b, thecircuit board 115 b is pressed down into the back connector 144 aligninglatches 145 with notches 115 j in the circuit board 115 b, and then thecircuit board 115 b is pushed forward so that the front end of thecircuit board 115 b is inserted into the front connector 142 and thelatches 145 engage with the notches 131 d. To unmate the transceiver 130from the circuit boards 119 a, 119 b, the front end of the circuit board115 b is pulled out of the front connector 142 such that the latches 145disengage with the notches 131 d and align with the notches 115 j, andthen the transceiver 130 is pulled out of the back connector 144.Preferably, the high-speed signals are transmitted through the frontconnector 142, and low-speed signals and/or power are transmittedthrough the back connector 144.

FIGS. 9A and 9B show a heatsink 151 for use with the transceiver 150shown in FIGS. 9C-9F. The transceiver 150 is preferably used in thefifth and sixth preferred embodiments of the present invention. Thetransceiver 150 can be used in the flat, co-planar environment of thefifth preferred embodiment shown in FIGS. 10A-10D and can be used in thestepped-plane environment of the sixth preferred embodiment shown inFIGS. 11A-11D.

As shown in FIGS. 9A and 9B, the heatsink 151 includes fins 151 a totransmit heat from the optical engine 115 a, protrusions 151 b or clips151 e to secure the circuit board 115 b, and cavity 151 c in which theoptical engine 115 a is located. Any suitable arrangement and number offins 151 a can be used as long as an adequate amount of heat can bedissipated from the optical engine 115 a. If the heatsink 151 includesprotrusions 151 b as shown, for example, in FIG. 9A, then a strap 151 dis used to secure the circuit board 115 b. The straps 151 d can be madeof a stamped metal or any other suitable material. The strap 151 dpreferably has a U-shape with a base and ends extending from the base.The ends of the strap 151 d includes holes that can engage with theprotrusions 151 b of the heatsink 151 to secure the circuit board 115 bto the heatsink 151. The base of the strap 151 d is positioned under thecircuit board 115 b, with the ends of the straps 151 d facing theheatsink 151. Pressing the base of the strap 151 d against the circuitboard 115 b, causes the ends of the strap 151 d to deflect over theprotrusions 151 b to cause the holes of the straps 151 d to engage withor snap together with the protrusions 151 b to secure the heatsink 151and circuit board 115 b together. Instead of using protrusions 151 b andstrap 151 d, it is also possible to use clips 151 e to secure thecircuit board 115 b as shown in FIGS. 9E and 9F. Although a single pairof opposing clips 151 e is shown in FIGS. 9E and 9F, it is possible touse more than one pair of opposing clips 151 e to secure the circuitboard 115 b.

It is possible to use any number and any suitable arrangement ofindividual lands in the lands 115 c, 115 d, 115 e. FIGS. 9E and 9F arebottom perspective views of the transceiver 150 showing differentpossible arrangements of the lands 115 d, 115 e on the bottom of thecircuit board 115 b. For example, it is possible to use more individuallands as seen by comparing the number of individual lands in lands 115 din FIG. 9E with the number of individual lands in lands 115 d in FIG.9F. It is also possible to use multiple rows of lands. For example,lands 115 e preferably include two rows of lands 115 e, instead of theone row of lands 115 e shown, for example, in FIG. 6D. If two rows oflands 115 e are used, then the circuit board 115 b can be mated to aback connector 154, 164 with two rows of contacts 154 a, 164 a as shown,for example, in FIGS. 10B and 11B.

It is also possible to provide the circuit board 115 b with guidefeatures to guide the transceiver 150 in the front connectors 152, 162shown, for example, in FIGS. 10A and 11A. FIGS. 9C and 9D show thecircuit board 115 b with holes 115 g that can be used in cooperationwith the posts 152 c, 162 c of the front connector 152, 162 shown, forexample, in FIGS. 10A and 11A. FIGS. 9E and 9F show the circuit board115 b with notches 115 h that can be used in cooperation with the ramps152 b, 162 b of the front connector 152, 162 shown, for example, inFIGS. 10B and 11B.

FIGS. 10A-10D show two-piece connector systems according to the fifthpreferred embodiment of the present invention. FIGS. 10A and 10B showthe circuit board 118 with front connectors 152 and back connectors 154.

The front connectors 152 are preferably edge-card connectors that matewith the front of the circuit board 115 b. Preferably, as seen in FIG.10D, the front connector 152 includes two rows of contacts 152 a, withone row of contacts 152 a that can engage the lands 115 c on top of thecircuit board 115 b and with the other row contacts 152 a that canengage the lands 115 d on bottom of the circuit board 115 b. The frontconnector 152 shown in FIG. 10A includes posts 152 c that engage withcorresponding holes 115 g in the circuit board 115 b.

The back connector 154 is preferably a zero-insertion-force connectorthat includes clips 155 that can be used to secure the back portion ofthe transceiver 150 (not shown in FIGS. 10A and 10B but shown in FIGS.10C and 10D) to the circuit board 118. The clips 155 can engage portionsof the circuit board 115 b that extend beyond the heatsink 151; however,it is also possible that the clips 155 engage portions of the heatsink151. The back connector 154 includes contacts 154 a that can engage thelands 115 e on the bottom of the circuit board 115 b. It is possible forthe back connector 154 to include a single row of contacts 154 a asshown in FIG. 10A or to include more than one row of contacts 154 a asshown in FIG. 10B.

As shown in FIG. 10D, to mate the transceiver 150 with the circuit board118, the front end of the circuit board 115 b is inserted into the frontconnector 152, and then the back end of the circuit board 115 b ispressed down into the back connector 154 such that the clips 155 engagewith the portions of the circuit board 115 b that extend beyond theheatsink 151. To unmate the transceiver 150 from the circuit board 118,a force is applied to the clips 155 to disengage the clips 155 from theportions of the circuit board 115 b that extend beyond the heatsink 151,and then the front end of the circuit board 115 b is pulled out of thefront connector 152. Preferably, the high-speed signals are transmittedthrough the front connector 152, and low-speed signals and/or power aretransmitted through the back connector 154.

FIGS. 11A-11D show two-piece connector systems according to the sixthpreferred embodiment of the present invention. FIGS. 11A and 11B showthe circuit board 119 b with the front connector 162 and the circuitboard 119 a with the back connector 164. The circuit board 119 b can bepart of an IC package; however, for simplicity, only the circuit board119 b is shown. As shown in FIG. 11D, the circuit boards 119 a, 119 bcan be connected together using solder balls 119 g.

The front connector 162 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, as seen in FIG.11D, the front connector 162 includes two rows of contacts 162 a, withone row of contacts 162 a that can engage the lands 115 c on top of thecircuit board 115 b and with the other row contacts 162 a that canengage the lands 115 d on bottom of the circuit board 115 b.

The back connector 164 is preferably a zero-insertion-force connectorthat includes clips 165 that can be used to secure the back portion ofthe transceiver 150 (not shown in FIGS. 11A and 11B but shown in FIGS.11C and 11D) to the circuit board 119 a. The back connector 164 can besimilar to the back connector 154 with the difference being that theheight of the back connector 164 is larger than the height of the backconnector 154. The back connector 164 includes a row of contacts 164 athat can engage the lands 115 e on the bottom of the circuit board 115b. It is possible for the back connector 164 to include a single row ofcontacts 164 a as shown in FIG. 11A or to include more than one row ofcontacts 164 a as shown in FIG. 11B.

As shown in FIG. 11D, to mate the transceiver 150 with the circuitboards 119 a, 119 b, the front end of the circuit board 115 b isinserted into the front connector 162 on the circuit board 119 b, andthen the back end of the circuit board 115 b is pressed down into theback connector 164 on the circuit board 119 a such that the clips 165engage with the portions of the circuit board 115 b that extend beyondthe heatsink 151. To unmate the transceiver 150 from the circuit boards119 a, 119 b, a force is applied to the clips 165 to disengage the clips165 from the portions of the circuit board 115 b that extend beyond theheatsink 151, and then the front end of the circuit board 115 b ispulled out of the front connector 162. Preferably, the high-speedsignals are transmitted through the front connector 162, and low-speedsignals and/or power are transmitted through the back connector 164.

FIGS. 12A and 12B show a heatsink 171 for use with the transceiver 170shown in FIGS. 12C and 12D. The transceiver 170 is used in the seventhand eighth preferred embodiments of the present invention. Thetransceiver 170 can be used in the flat, co-planar environment of theseventh preferred embodiment shown in FIGS. 13A and 13B and can be usedin the stepped-plane environment of the eighth preferred embodimentshown in FIGS. 14A and 14D.

As shown in FIGS. 12A and 12B, the heatsink 171 includes fins 171 a totransmit heat from the optical engine 115 a, legs 131 b and post 171 dto secure the circuit board 115 b, and cavity 171 c in which the opticalengine 115 a is located. Any suitable arrangement and number of fins 171a can be used as long as an adequate amount of heat can be dissipatedfrom the optical engine 115 a. The post 171 d of the heatsink 171includes a hole 171 e through which the screw 175 is inserted to securethe circuit board 115 b. As seen in FIG. 12D, the circuit board 115 bpreferably includes a tab 115 i with a hole through which the screw 175is inserted.

FIGS. 13A and 13B show a two-piece connector system according to theseventh preferred embodiment of the present invention. FIGS. 13A and 13Bshow the circuit board 118 with front connectors 172 and back connectors174.

The front connectors 172 are preferably edge-card connectors that matewith the front of the circuit board 115 b. Preferably, the frontconnector 172 includes two rows of contacts 172 a, with one row ofcontacts 172 a that can engage the lands 115 c on top of the circuitboard 115 b and with the other row contacts 172 a that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 174 is preferably a zero-insertion-force connector.Retainer 175 a can be used to secure the heatsink 171 (not shown in FIG.13A and but shown in FIG. 13B) to the circuit board 118. The screw 175can be inserted into a hole 175 b of the retainer 175 a. The screw 175secures the transceiver 170 to the circuit board 118 by being insertedthrough the holes 171 e, 175 b in the heatsink 171, the circuit board115 b, and the retainer 175 b. The back connector 174 includes contacts174 a that can engage the lands 115 e on the bottom of the circuit board115 b. It is possible for the back connector 174 to include a single rowof contacts 174 a as shown in FIG. 13A or to include more than one rowof contacts 174 a.

To mate the transceiver 170 with the circuit board 118, the front end ofthe circuit board 115 b is inserted into the front connector 172, andthen the screw 175 is used to secure the transceiver 170 to the circuitboard 118. To unmate the transceiver 150 from the circuit board 118, thescrew 175 is unscrewed from at least the retainer 175 a, and then thefront end of the circuit board 115 b is pulled out of the frontconnector 172. Preferably, the high-speed signals are transmittedthrough the front connector 172, and low-speed signals and/or power aretransmitted through the back connector 174.

FIGS. 14A and 14B show a two-piece connector system according to theeighth preferred embodiment of the present invention. FIGS. 14A and 14Bshow the circuit board 119 b with the front connector 182 and thecircuit board 119 a with the back connector 184. The circuit board 119 bcan be part of an IC package; however, for simplicity, only the circuitboard 119 b is shown.

The front connector 182 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, the frontconnector 182 includes two rows of contacts 182 a, with one row ofcontacts 182 a that can engage the lands 115 c on top of the circuitboard 115 b and with the other row contacts 182 a that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 184 is preferably a zero-insertion-force connector.Retainer 185 a can be used to secure the heatsink 171 (not shown in FIG.14A and but shown in FIG. 14B) to the circuit board 119 a. The screw 175can be inserted into a hole 185 b of the retainer 185 a. The screw 175secures the transceiver 170 to the circuit board 119 a by being insertedthrough the holes 171 e, 185 b in the heatsink 171, the circuit board115 b, and the retainer 175 b. The back connector 184 includes contacts184 a that can engage the lands 115 e on the bottom of the circuit board115 b. It is possible for the back connector 184 to include a single rowof contacts 184 a as shown in FIG. 14A or to include more than one rowof contacts 184 a.

To mate the transceiver 170 with the circuit boards 119 a, 119 b, thefront end of the circuit board 115 b is inserted into the frontconnector 182 on the circuit board 119 b, and then the screw 175 is usedto secure the transceiver 170 to the circuit board 119 a. To unmate thetransceiver 170 from the circuit boards 119 a, 119 b, the screw 175 isunscrewed from at least the retainer 185 a, and then the front end ofthe circuit board 115 b is pulled out of the front connector 182.Preferably, the high-speed signals are transmitted through the frontconnector 182, and low-speed signals and/or power are transmittedthrough the back connector 184.

FIGS. 15A and 15B show a heatsink 191 for use with the transceiver 190shown in FIGS. 15E and 15F. FIGS. 15C and 15D show how a U-clip 191 d isused to secure the heatsink to the circuit boards 118, 119 a. Thetransceiver 190 is preferably used in the ninth and tenth preferredembodiments of the present invention. The transceiver 190 can be used inthe flat, co-planar environment of the ninth preferred embodiment shownin FIGS. 16A and 16B and can be used in the stepped-plane environment ofthe tenth preferred embodiment shown in FIGS. 17A and 17B.

As shown in FIGS. 15A and 15B, the heatsink 191 includes tines 191 a totransmit heat from the optical engine 115 a, a U-clip 191 d that engageswith the notches 195, 205 shown in FIG. 16A-17B to secure the circuitboard 115 b as well as the heatsink 191, cavity 191 c in which theoptical engine 115 a is located. The heatsink 191 also preferablyincludes slots 191 i in which the U-clip 191 d is inserted. Each of theslots 191 i preferably includes a ramp 191 h that engages the top of thearm 191 f and that stops the U-clip 191 d from being inserted past theramp 191 h and preferably includes depressions 191 j, 191 k that engagethe bottom of the arm 191 f. Depressions 191 j are arranged to engagethe bottom of the arm 191 f to stop the U-clip 191 d from being pulledout of the heatsink 191. Depressions 191 k are also arranged to engagethe bottom of the arm 191 f when the legs 191 e are engaged with thenotches 195, 205 to provide a resistance when the U-clip 191 d ispulled-up to disengage the legs 191 e from the notches 195, 205.

Any suitable arrangement and number of tines 191 a can be used as longas an adequate amount of heat can be dissipated from the optical engine115 a. In addition, any length of the tines 191 a can be used. Thecavity 191 c is preferably arranged to allow the cables 116 to be angledwith respect to the circuit boards 118, 119 a as shown in FIGS. 16B and17B. By angling the cables 116, it is possible to reduce the size of thefootprint required on the circuit boards 118, 119 a and to reduce thebend angle of the cable 116. Reducing the bend angle of the cable 116reduces the possibility of damaging the optical fibers in the cable 116.

FIGS. 15C and 15D show the U-clip 191 d. U-clip 191 d preferablyincludes legs 191 e, arms 191 f, and tab 191 g. The tab 191 g isarranged such that a force from, for example, a human finger, can pushthe legs 191 e into the notches 195, 205 of the back connector 194, 204as shown, for example, FIGS. 16A and 17A and can pull the legs 191 efrom the notches 195, 205 of the back connector 194, 204.

FIGS. 16A and 16B show a two-piece connector system according to theninth preferred embodiment of the present invention. FIG. 16A shows thecircuit board 118 with the front connector 192 and the back connector194.

The front connector 192 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, the frontconnector 192 includes two rows of contacts (not seen in FIG. 16A), withone row of contacts that can engage the lands 115 c on top of thecircuit board 115 b and with the other row contacts that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 194 is preferably a zero-insertion-force connectorthat includes notches 195 that can be used with U-clip 191 d to securethe back portion of the transceiver 190 (not shown in FIG. 16A but shownin FIG. 16B) to the circuit board 118. The back connector 194 includes arow of contacts 194 a that can engage the lands 115 e on the bottom ofthe circuit board 115 b. Although a single row of contacts 194 a isshown in FIG. 16A, it is also possible to use more than one row ofcontacts 194 a.

To mate transceiver 190 with the circuit board 118, the circuit board115 b is pressed down into the back connector 194 so that posts 196align with notches 115 j in the circuit board 115 b, and then thecircuit board 115 b is pushed forward so that the front end of thecircuit board 115 b is inserted into the front connector 192. Then, theU-clip 191 d can be pushed down such that the legs 191 e engage thenotches 195. To unmate the transceiver 190 from the circuit board 118,the U-clip 191 d can be pulled up such that the legs 191 e disengagewith the notches 195. Then the front end of the circuit board 115 b ispulled out of the front connector 192 so that the posts 196 align withthe notches 115 j, and then the transceiver 190 is pulled out of theback connector 194. Preferably, the high-speed signals are transmittedthrough the front connector 192, and low-speed signals and/or power aretransmitted through the back connector 194.

FIGS. 17A and 17B show a two-piece connector system according to thetenth preferred embodiment of the present invention. FIG. 17A shows thecircuit board 119 b with the front connector 202 and the circuit board119 a with the back connector 204. The circuit board 119 b can be partof an IC package; however, for simplicity, only the circuit board 119 ais shown.

The front connector 202 is preferably an edge-card connector that mateswith the front of the circuit board 115 b. Preferably, the frontconnector 202 includes two rows of contacts (not seen in FIG. 17A), withone row of contacts that can engage the lands 115 c on top of thecircuit board 115 b and with the other row contacts that can engage thelands 115 d on bottom of the circuit board 115 b.

The back connector 204 is preferably a zero-insertion-force connectorthat includes notches 205 that can be used with U-clip 191 d to securethe back portion of the transceiver 190 (not shown in FIG. 17A but shownin FIG. 17B) to the circuit board 119 a. The back connector 204 can besimilar to the back connector 194 with the difference being that theheight of the back connector 204 is larger than the height of the backconnector 194. The back connector 204 includes a row of contacts 204 athat can engage the lands 115 e on the bottom of the circuit board 115b. Although a single row of contacts 204 a is shown in FIG. 17A, it isalso possible to use more than one row of contacts 204 a.

To mate transceiver 190 with the circuit boards 119 a, 119 b, thecircuit board 115 b is pressed down into the back connector 204 so thatposts 206 align with notches 115 j in the circuit board 115 b, and thenthe circuit board 115 b is pushed forward so that the front end of thecircuit board 115 b is inserted into the front connector 202. Then, theU-clip 191 d can be pushed down such that the legs 191 e engage thenotches 205. To unmate the transceiver 190 from the circuit boards 119a, 119 b, the U-clip 191 d can be pulled up such that the legs 191 edisengage with the notches 205. Then the front end of the circuit board115 b is pulled out of the front connector 202 so that the posts 206align with the notches 115 j, and then the transceiver 190 is pulled outof the back connector 204. Preferably, the high-speed signals aretransmitted through the front connector 202, and low-speed signalsand/or power are transmitted through the back connector 204.

Instead of using the latches 135, 145, clips 155, 165, screws 175, or aU-clip 191 d of the various preferred embodiments of the presentinvention described above, it is also possible to use other arrangementsto secure the circuit board 115 b to the heatsink 131, 151, 171,including, for example, staples or epoxy.

It should be understood that the foregoing description is onlyillustrative of the present invention. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the present invention. Accordingly, the present inventionis intended to embrace all such alternatives, modifications, andvariances that fall within the scope of the appended claims.

What is claimed is:
 1. An interconnect system comprising: a host circuitboard; an IC package connected to the host circuit board and including afirst connector, an IC circuit board, and an IC die; and a transceiverincluding an optical engine arranged to convert optical signals intoelectrical signals and arranged to convert electrical signals intooptical signals; wherein the transceiver is arranged to mate and tounmate with the first connector so that, when the transceiver is matedwith the first connector, at least some electrical signals transmittedto and from the IC die are transmitted only on or through the IC circuitboard.
 2. An interconnect system according to claim 1, wherein the ICcircuit board includes a plurality of solder balls arranged in a ballgrid array.
 3. An interconnect system according to claim 1, wherein thefirst connector is an edge-card connector.
 4. An interconnect systemaccording to claim 1, wherein the transceiver further includes aheatsink.
 5. An interconnect system according to claim 4, wherein: thetransceiver further includes a transceiver circuit board; and theheatsink includes a pair of legs that are arranged to connect thetransceiver circuit board to the heat sink.
 6. An interconnect systemaccording to claim 4, wherein: the transceiver further includes atransceiver circuit board; and the heatsink includes a pair ofprotrusions and a strap that are arranged to connect the transceivercircuit board to the heat sink.
 7. An interconnect system according toclaim 4, wherein: the transceiver further includes a transceiver circuitboard; and the heatsink includes a pair of opposing clips that arearranged to connect the transceiver circuit board to the heat sink. 8.An interconnect system according to claim 4, wherein: the transceiverfurther includes a transceiver circuit board; and the transceiver isconnected to the host circuit board with a screw.
 9. An interconnectsystem according to claim 1, wherein the IC package further includes alid.
 10. An interconnect system according to claim 9, wherein the lidprovides a heat path for the optical engine when the transceiver ismated with the first connector.
 11. An interconnect system according toclaim 1, wherein the transceiver includes a cable through which thetransceiver receives and transmits optical signals.
 12. An interconnectsystem according to claim 11, wherein the optical signals are convertedto electrical signals and transmitted to the IC package through thefirst connector.
 13. An interconnect system according to claim 12,wherein the electrical signals are further transmitted to the IC diethrough the first connector and the IC circuit board.
 14. Aninterconnect system according to claim 1, wherein the transceiverincludes a cable through which the transceiver receives and transmitselectrical signals.
 15. An interconnect system according to claim 1,wherein the IC package includes at least one additional first connector.16. An interconnect system comprising: a first circuit board; first andsecond connectors connected to the first circuit board; and atransceiver including an optical engine and arranged to receive andtransmit optical signals through a cable, to convert optical signalsreceived from the cable into electrical signals, and to convertelectrical signals received from the first connector into opticalsignals to be transmitted through the cable; wherein the transceiver isarranged to mate and to unmate with the first and second connectors sothat, when the transceiver is mated with the first and secondconnectors, at least some converted electrical signals are transmittedto the first connector and so that at least some electrical signalsreceived from the cable are transmitted to the second connector.
 17. Aninterconnect system according to claim 16, wherein the first connectoris connected to the first circuit board through a second circuit board.18. An interconnect system according to claim 16, wherein thetransceiver is arranged to receive and transmit electrical signalsthrough the cable.
 19. An interconnect system according to claim 16,wherein the cable is permanently attached to the transceiver.
 20. Aninterconnect system comprising: a host circuit board; an IC packageconnected to the host circuit board and including a first connector, anIC circuit board, and an IC die; and a transceiver arranged to mate andto unmate with the first connector so that, when the transceiver ismated with the first connector at least some electrical signalstransmitted to and from the IC die are transmitted only on or throughthe IC circuit board; wherein only electrical signals are transmittedbetween the transceiver and the IC package.
 21. An interconnect systemaccording to claim 20, wherein the IC circuit board includes a pluralityof solder balls arranged in a ball grid array.
 22. An interconnectsystem according to claim 20, wherein the first connector is anedge-card connector.
 23. An interconnect system according to claim 20,wherein the transceiver includes a cable through which the transceiverreceives and transmits electrical signals.
 24. An interconnect systemaccording to claim 20, wherein: the transceiver includes a circuit boardand a cavity; and the cavity and the circuit board are arranged suchthat the cable is attached to the circuit board at an angle with respectto the circuit board.
 25. An interconnect system according to claim 20,wherein: the transceiver further includes an optical engine arranged toconvert optical signals into electrical signals and arranged to convertelectrical signals into optical signals; and the electrical signals thatare transmitted between the transceiver and the IC package include theoptical signals converted into electrical signals.
 26. An interconnectsystem according to claim 25, wherein optical signals are converted toelectrical signals and transmitted to the IC package through the firstconnector.
 27. An interconnect system according to claim 20, wherein theIC package includes at least one additional first connector.
 28. Aninterconnect system comprising: a first circuit board; first and secondconnectors connected to the first circuit board; and a transceiverarranged to receive and transmit electrical signals through a cable;wherein the transceiver is arranged to mate and to unmate with the firstand second connectors so that, when the transceiver is mated with thefirst and second connectors, the electrical signals received from thecable are transmitted to either the first connector or the secondconnector and so that electrical signals received from either the firstconnector or the second connector are transmitted to the cable; and onlyelectrical signals are transmitted between the transceiver and the firstcircuit board.
 29. An interconnect system according to claim 28,wherein: the first connector is connected to the first circuit boardthrough a second circuit board; and only electrical signals aretransmitted between the transceiver and the second circuit board.
 30. Aninterconnect system according to claim 28, wherein the cable ispermanently attached to the transceiver.
 31. An interconnect systemaccording to claim 28, wherein: the transceiver further includes anoptical engine arranged to convert optical signals into electricalsignals and arranged to convert electrical signals into optical signals;and the electrical signals that are transmitted between the transceiverand the first circuit board include the optical signals converted intoelectrical signals.